he legitimately is afraid that a cop will pull him over inside the tunnel.. when i told him that its actually illegal for a cop to do that he told me that i was lying and that they have special cameras to see people speeding in tunnels

The speed limit is actually lower in some of the tunnels (Ft. Pitt in particular)

The bigger issue is actually the major intersections just on the other side of the tunnels (Ft. Pitt, Sq Hill, etc.)-- these cause traffic to back up INTO the tunnels and/or standing waves in the tunnels.